how do I remove my photos and videos from icloud - step by step

See the articles https://support.apple.com/en-in/HT204264

https://support.apple.com/en-in/guide/photos/pht5156cc968/4.0/mac/10.14

https://support.apple.com/en-in/HT207368

https://support.apple.com/en-in/guide/photos/pht6e157c5f/mac

Export photos from system photo library to a desired location say download folder in finder and connect an external hard drive to the Mac https://support.apple.com/en-in/guide/mac-help/mchl027f1d66/mac , then transfer the photos from download folders into the external hard drive , hence all your photo data is saved .

You can select few photos see this article Select and deselect photos in Photos on Mac - Apple Support and delete to recently deleted folder see this article Delete photos or recover deleted ones in Photos on Mac - Apple Support ( its your choice to delete them permanently immediately or after 30 days the photos will be removed from the iCloud server ) .

In this way the complete photo data is still on external hard drive , but the space is reduced in photo library .

Do you want to delete them permanently or do you want to transfer them to a computer or external hard drive?